High temperature oxidation of AlCrFe complex metallic alloys

Isothermal oxidation of Al65Cr27Fe8 and Al80Cr15Fe5 was studied in the 600-1080 °C range. Formation of transient alumina layers is obtained up to 900 °C. On Al65Cr27Fe8 transient to α-phase transformations occur when performing oxidation at 1000 °C, together with the possible appearance of (Al0.9Cr0.1)2O3. At 1080 °C, direct formation of α-alumina is obtained. On Al80Cr15Fe5, spallation of the oxide layer during the cooling stage is observed following oxidation at 800 and 900 °C, revealing thermal etching of the underneath alloy surface. At 1050 °C the α-Al2O3 scale is directly formed but plastic deformation and recrystallization of the underneath alloy into several intermetallic phases is observed.